Firefox users who are looking to either disguise or change the title of their tabs will want to take a look at the add-on, Page Title Eraser.

From the description:

The Page Title Eraser adds menu item to the page context menu and “Tools” menu items. “Right-click” menu includes a “Hide title” menu item now. Using this item you can hide/show tab and window titles and tab icon. Each tab has its independent instance of this item.

I find use for this tab because certain sites I use display just the record ID numbers in the title bar, so it makes it very hard to distiguish what I have open on each tab without jumping back and forth. With this extension I can rename the tab to exactly what I am looking at so there is no confusion.

Interestingly enough, the author wrote this extension because they didn’t want people looking over their shoulder:

I always open several tabs in a Firefox window, but I would not like other people see some of tabs labels. So I wrote the PTE extension which helps me to have such feature.

So you can use this to be sneaky as well.